Safety device for elevators.



I. W. THROGKMORTON. SAFETY DEVICE FOR ELEVATORS. APPLICATION FILED MAR. 28, 1914.

1,1 18,1 62. Patented Nov. 24, 1914. 1&0!

HE NORRIS PETERS C0,, FHO70-LITHQ, WASHING rorv. D. C.

UTED

ISAAC THROCKMORTON, F RICHMOND, VIRGINIA.

SAFETY DEVICE FOR ELEVATORS.

Application filed March as, 1914.

This invention relates to new and useful I improvements in elevators, and particularly to safety devices therefor.

An object of this invention is the provision of an elevator having a device connected thereto, for the purpose of automatically stopping the descent thereof, upon breaking of the lifting cable.

Another object of this invention resides in a safety device, comprising a pair of looking pawls which are connected by bell-crank levers to the lift cable of an elevator, means being provided to force the pawls into engagement with rack bars carried upon the walls of the elevator shaft, upon breaking of the cable.

With these and other objects in view, my invention consists in the novel construction, combination and arrangement of parts to be hereinafter more fully described, claimed and illustrated in the accompanying drawings, in which Figure 1 is a fragmentary top plan view of an elevator car, showing my improved safety device connected thereto; Fig. 2 is a side elevation thereof; and Fig. 3 is a section on the line 83 of Fig. 2.

Referring more particularly to the drawings, the numeral 5 designates apair of vertical posts arranged on opposite sides of an elevator shaft, and mounted upon the inner face of each post are a pair of spaced guide bars 6, which are adapted to guide the elevator in its vertical movement in the shaft. The elevator which in the illustration is shown as a freight elevator, comprises transversely extending beams 7 which support the floor 8 of the carriage, and extending-upwardly from the outermost beams are pairs of converging brace rods 9, which are connected at their upper ends to the opposite ends of the transversely extending head 10 of the carriage. The head 10 extends to the guide bars 6 on the opposite sides of the shaft, and the extremities of the rods 9 project above the head and are connected to a pair of curved truss bars 11 Specification of Letters Patent.

Patented Nov. 24:, 1914.

Serial No. 827,994.

adjacent their opposite ends. The bars 11 are spaced apart, and their extremities engage the outer faces of the guide bars 6 to prevent rocking of the carriage as it moves in the shaft. The bars 11 are braced intermediate of their ends by the vertical braces 12, and are maintained in spaced relation by the sleeves 13 which are mounted on bolts 14, which extend through the bars at various longitudinal points thereof. Pivotally mounted on one of the bolts adjacent each end of the truss bars are a pair of bellcrank levers 15, one arm 16 of each lever extending inwardly of the bars, the extremities of the arms 16 terminating closely adjacent each other and being formed with openings 17 'therein,'to receive the ends of asplit cable 18, which is connected to a suitable operating mechanism (not shown). The other arm 19 of each lever extends downwardly, and the extremity of each arm is pivotally connected to the inner end of a clutch or pawl 20, the lower edge of which engages in a longitudinal groove 21 formed in the upper face of the head 10. The other end of each pawl is disposed. between the outermost sleeve 13 at each end of the bars 11 and the upper face of the head 10 to maintain the pawls in horizontal position. Arranged in a vertical groove 22 in the inner face of each post 5 is a rack bar 23, the teeth 24: of which extend inwardlybetween the guide bars 11, the pawls being adapted for engagement with the teeth upon breaking of the cable as will be hereinafter more fully described. the head 10 intermediate of its ends. are a pair of contractile coiled springs 25, the upper end of each spring being connected in the opening 17 in one of the levers 15, to normally draw downwardly upon the same against the pull of the cable.

In the practical use of mv invention, the carriage is moved upwardly and downwardly, in the shaft, by suitable mechanism (not shown) to which the cable is connected, and the arms 16 of the bell crank levers are maintained in their upper position against the intermediate sleeves 13 by reason of their engagement with the cable, whereby the pawls are held out of engagement with the rack bars 23. Should the cable 18 break while the car is ascending or descending, the springs 25 will draw downwardly upon the arms 16 of the levers 15 thereby moving the arms 19 of the levers outwardly,

Connected at one end to to force the pawls into engagement With the teeth 24 of the rack bars and prevent the car from chopping to the end of the shaft.

From the above description, taken in connection with the accompanying drawings, it will be seen that my improved safety device Will act instantaneously upon the breaking of the cable to stop the descent of the car.

\Vhile I have shown the device as connected to freight elevator, it Will be understood that it may be readily and efi'ectively connected to a passenger elevator of any description.

Haring thus fully described my invention, What I claim and desire to secure by Letters Patent is:

1. T he combination with an elevator car, of a pair of vertical posts arranged on opposite sides of said elevator, spaced guide bars connected to the inner face of each post, a rack bar carried by each post b tween said guide bars, a pair of spaced upwardly curved truss bars connected to the top of said car, the opposite ends of said bars projecting beyond the opposite sides of said car and engaging said guide bars, bo'lts connecting said truss bars, sleeves mounted on said bolts to maintain the truss bars in their spaced relation, a bell-crank lever pivotally mounted on one of said bolts adjacent the opposite ends of said bars, one arm of each of said levers being connected at its extremity to the operating cable, and

means connected to the other arm of each of said levers to engage said rack bars to stop the descent of said car upon breaking of the cable.

2; The combination with an elevator car, of a pair of vertical. posts arranged on opposite sides of said elevator, spaced guide bars connectedto the inner face of each post, a rack bar carried by each post between said guide bars, a pair of spaced upwardly curved truss bars connected to the top of said car, the opposite end of said bars projecting beyond the opposite sides of said car and enga said guide bars, bolts connecting said truss bars, sleeves mounted on said bolts to maintain the truss bars in their spaced relation, bell-crank lever pivotally mounted on one of said bolts adjacent the opposite ends of said bars, one arm of each of said levers being connected at its er:- tremity to the operating table, contractile springs connected at one end to the top of said car, the other end of each spring being connected to the extremity of one of the arms of the bell-crank levers, and paWls connected to the other arm of the lovers for engagement with the rack bars upon breaking of the cable.

In testimony whereof I hereunto a'liix my signature in the presence of two Witnesses.

ISAAC XV. THROCKMORTON. lVitnesses:

S. L. ULLMAN,

R. B. VAUGHAN.

copies or this patent may be obtained for five cents each, by addressing the Commissioner of Patents.

Washington, D. G. 

